As problematic noises of a hybrid vehicle where two electric motors are provided via a backlash on a power transmission path extending from an internal combustion engine to drive wheels, there are known to be booming noise which occurs by vibration of the power transmission path, the vibration being excited by torque pulsation of the internal combustion engine, and rattling noise which occurs by collision of gears at the backlash when motor torque crosses 0 Nm. Although the backlash generally indicates a gap between gears engaging with each other, here, a gap existing in a rotational direction of two members locked by spline-coupling or the like so as to be twisted to each other is also treated as the backlash. Accordingly, noise which occurs by collision of such two members at the backlash during their rotation is also one kind of the rattling noise.
There is known to be a control apparatus for suppressing the booming noise, where a torque pulsation component is calculated from torque of a crank shaft of an internal combustion engine, a pulsation compensating torque for removing the torque pulsation component from torque of a drive shaft is calculated based on the toque pulsation component calculated and a torque transmission function from the internal combustion engine to the drive shaft, and the pulsation compensating torque calculated is subtracted from a torque command value of a second electric motor, thereby the torque command value is corrected (the patent literature #1). Further, there is known to be a control apparatus for suppressing the rattling noise, which executes a pressing control where the second electric motor is made to output pressing torque for preventing motor torque of the second electric motor from reaching 0 Nm, and a gear train and the like connected to the second electric motor are held in a state that they are pressed in one direction (the patent literature #2).